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User name fansler
Log entry time 13:36:58 on October 06, 2009
Entry number 293477
keyword=Hall A Trips
We went into the hall to investigate multiple magnet trips. We found the
left Q1 relief valve going off. The electronics on the cold return valve
were failing causing it to open and close arbitrarily. This in turn
caused an overpressure problem in the magnet affecting the lead flows of
LQ1, and subsequently all lead flows. The lead flow interlocks tripped
forcing the magnets into fast shut down, which caused the liquid level to
boil off and the cryostats to empty. We have opened the cold return
valve on the LQ1 and unplugged the valve to prevent further interruptions
in operations. As a safeguard we unplugged the return valves on both
Q1's cold returns verified open, warm returns verified closed. If these
valved need to be moved, the hall A technical staff will have to restore
power. We also discovered that the Q1 and Dipole lead flow read backs
have an offset. The numbers displayed on the GUI are 8 SLM higher that
the actual lead flow. We adjusted the lead flows per the front panel
read back. We will investigate the lead flow offset, and make
corrections as required.